1. Field of the Invention
The present invention relates to a substrate treatment apparatus and a substrate treatment method for removing an unnecessary substance from a surface of a substrate. Examples of the substrate to be treated include semiconductor wafers, glass substrates for liquid crystal display devices, glass substrates for plasma display devices, substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks and substrates for photo-masks.
2. Description of Related Art
Production processes for semiconductor devices and liquid crystal display devices often employ a substrate treatment apparatus for removing unnecessary substances such as particles and metal impurities (including unnecessary metal ions typified by copper ions) from a surface of a substrate. Where the substrate treatment apparatus is adapted to perform a treatment on a substrate-by-substrate basis, for example, ozone water and an HF (hydrofluoric acid) solution are alternately and repeatedly supplied to the substrate surface while the substrate is rotated within a generally horizontal plane. By the supply of the ozone water, an oxide film is formed on the substrate surface. By the subsequent supply of the HF solution, the particles on the substrate surface are removed together with the oxide film, and the metal impurities are removed from the substrate surface.
However, the particle removing effect of such a treatment depends on the amount of the etching of the oxide film by the HF solution. In order to provide a sufficient particle removing effect, a substrate surface etching amount should be increased, thereby requiring a longer process time.
Further, the substrate surface is liable to be over-etched in order to achieve the sufficient particle removing effect. If the substrate surface is over-etched, a hydrophobic base of the substrate is exposed, so that the particles once removed in the HF solution adhere again on the exposed hydrophobic base.